你說的是二分法查找數組中某個元素的下標吧

public?class?Binary?{

	public?static?void?main(String[]?args)?{
		int[]?arr?=?{1,2,3,5,8};
		System.out.println(binaryFind(arr,8));
	}
	public?static?int?binaryFind(int[]?arr,int?value){
		int?low=0,high=arr.length?-?1;
		while(low?<=?high){
			int?midle?=?(low?+?high)?/?2;
			midle?=?(low?+?high)?/?2;
			if(arr[midle]?==?value){
				return?midle;
			}
			if(arr[midle]?>?value){
				high?=?midle?+?1;
			}else{
				low?=?midle?+?1;
			}
		}
		return?-1;
	}
}